Recently, as further miniaturization of large scale integrated circuits (LSI) proceeds, a technology for processing a more delicate structure is demanded. In response to such demand, an attempt has already been started in which a fine pattern is formed using a phase-separated structure formed by self-assembly of a block copolymer having mutually incompatible blocks bonded together.
For using a phase separation of a block copolymer, it is necessary to form a self-assembled nano structure by a microphase separation only in specific regions, and arrange the nano structure in a desired direction. For realizing position control and orientational control, graphoepitaxy to control phase-separated pattern by a guide pattern and chemical epitaxy to control phase-separated pattern by difference in the chemical state of the substrate are proposed (see, for example, Non-Patent Document 1).
One method that has been proposed for achieving favorable phase separation of a block copolymer, thus enabling formation of a very fine pattern, is a method in which a neutral layer having a surface free energy that is between the surface free energy values of two block chains is formed on the substrate, so that the surface free energy of the surface on the substrate with which the block copolymer makes contact is a surface free energy value that is between the surface free energy values of the two block chains (for example, see Patent Document 1).
Further, Non-Patent Document 2 discloses that a method of forming an under layer film by using a compound having heat-crosslinkable property.